Viscous liquids or fluids are applied by dispensers onto a surface of a substrate in a variety of dispensing applications employed in the manufacture of products and product packaging. These viscous liquids include thermoplastic materials such as hot melt adhesives. Liquid dispensers utilize pneumatically or electrically actuated valve assemblies for metering a precise quantity of the viscous liquid and discharging the metered amount through a small-diameter dispensing orifice. Many thermoplastic materials exist in a solid form at room or ambient temperature and must be heated to create a flowable viscous liquid. Other hot melt adhesive materials are supplied as liquids at room temperature. A solid form of material is placed in a holding tank having heated walls and is melted by heating the solid material above its melting point. The viscous liquid is pumped in a molten state under pressure from the holding tank through a supply conduit to a manifold block. The manifold block has liquid passageways connected in fluid communication with the dispensing orifice of one or more liquid dispensers.
A dispensing module that includes the dispensing orifice is usually connected to the manifold, (sometimes referred to as a service block or gun manifold), by way of screws or bolts that extend through the module and into threaded holes in the face of the gun manifold. The combined service block or manifold and the module is typically referred to as a gun. In order for the liquid dispensing system to operate properly, this connection of the manifold with the module must be accomplished so that liquid ports on each of the manifold and module are properly aligned so as to provide leak-proof fluid communication between the two subassemblies or components. In the case of a pneumatically operated module and/or one which provides air-assisted liquid dispensing, cross-connection of an air port with an adhesive port must be avoided. Connecting the two subassemblies entails placing the module in its proper position and then, while holding the module steady, threading the connecting bolts through the module into the manifold. Misalignment during the assembly process may cause the adhesive to leak from the gun onto a conveying system and/or substrate as well as to leak into the air section of the module.
Oftentimes, operational or maintenance personnel will need to remove the module from the manifold for such purposes as cleaning or attaching a different module. Thus, a need exists for an interface between a module and a gun manifold that simplifies attachment of the module, prevents misalignment of the two subassemblies and their respective liquid ports during attachment, reduces the likelihood of liquid leaking into the air section, and prevents misconnecting the two subassemblies.